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Process for the preparation of 3-(3-chloro-1h-pyrazol-1-yl)pyridine

A technology for pyridine and pyrazole, which is applied in the field of improved preparation of 3-pyridine,-pyrazolidine-3-carboxylate, and can solve problems such as difficult product separation, low yield, and difficult preparation of 3-chloropyrazole

Inactive Publication Date: 2017-08-18
DOW AGROSCIENCES LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The disclosed process produces low yields which are dependent on the starting material which is difficult to prepare (3-chloropyrazole) and the resulting product is difficult to isolate in pure form

Method used

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  • Process for the preparation of 3-(3-chloro-1h-pyrazol-1-yl)pyridine
  • Process for the preparation of 3-(3-chloro-1h-pyrazol-1-yl)pyridine
  • Process for the preparation of 3-(3-chloro-1h-pyrazol-1-yl)pyridine

Examples

Experimental program
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Effect test

preparation example Construction

[0025] The present invention provides an improved process for the preparation of 3-(3-chloro-1H-pyrazol-1-yl)pyridine (5b) by reacting 3-hydrazinopyridine dihydrochloride with dialkyl maleate Cyclization affords alkyl 5-oxo-2-(pyridin-3-yl)pyrazolidine-3-carboxylate (10a), which by chlorination affords 3-chloro-1-(pyridin-3-yl)- 4,5-Dihydro-1H-pyrazole-5-carboxylic acid alkyl ester (10b), by oxidation to give 3-chloro-1-(pyridin-3-yl)-1H-pyrazole-5-carboxylic acid alkyl ester (10c), converted to carboxylic acid by hydrolysis of the ester to give 3-chloro-1-(pyridin-3-yl)-1H-pyrazole-5-carboxylic acid hydrochloride (10d), and removal by decarboxylation carboxylic acid.

[0026] In the first step, the alkali metal (C 1 -C 4 ) alkoxide in the presence of (C 1 -C 4 ) in fatty alcohol with dialkyl maleate to process 3-hydrazinopyridine dihydrochloride to obtain 5-oxo-2-(pyridin-3-yl)pyrazolidine-3-carboxylic acid alkyl ester ( 10a). Although stoichiometric amounts of 3-hydra...

Embodiment

[0038] 1. Preparation of ethyl 5-oxo-2-(pyridin-3-yl)pyrazolidine-3-carboxylate (10a)

[0039]

[0040] A four-neck round bottom flask (250 mL) was charged with sodium ethoxide (21 wt% in ethanol, 56 mL, 192 mmol). 3-Hydrazinopyridine·dihydrochloride (10.0 g, 55.0 mmol) was added, resulting in an exotherm raising the temperature from 20°C to 32°C. The reaction was allowed to cool to 20 °C, diethyl maleate (13.4 mL, 82.0 mmol) was added and the reaction was heated at 60 °C for 3 hours (h). The reaction was cooled to 20°C and quenched with acetic acid. The reaction mixture was diluted with water (100 mL) and extracted with ethyl acetate (3 x 100 mL). The combined organics were concentrated to dryness and the residue was purified by flash column chromatography using ethyl acetate as eluent as the title compound (6.60 g, 51%) as a blue oil: 1 H NMR (400MHz, DMSO-d 6 )δ10.40(s,1H),8.40–8.26(m,1H),8.19(dd,J=4.4,1.6Hz,1H),7.47–7.21(m,2H),4.77(dd,J=9.8, 2.1Hz, 1H), 4.22(qd, ...

Embodiment A

[0061] Example A Bioassays on Green Peach Aphid ("GPA") (Myzus persicae) (MYZUPE).

[0062] GPA is the most important aphid pest of peach trees, causing reduced growth, shriveling of leaves and death of various tissues. It is also dangerous because it acts as a vector for the transport of plant viruses, such as potato virus Y and potato leafroll virus (for members of the nightshade / potato family Solanaceae), and various mosaic viruses (for many other grain crop). GPA attacks plants such as broccoli, burdock, cabbage, carrots, cauliflower, daikon, eggplant, kidney beans, lettuce, macadamia nuts, papaya, peppers, sweet potatoes, tomatoes, watercress, and zucchini, among others. GPA also attacks many ornamental crops such as carnations, chrysanthemums, flowering white cabbage, orangutan and roses. GPA has developed resistance to many insecticides.

[0063] Several molecules disclosed herein were tested for GPA using the procedure described below.

[0064] Cabbage seedlings (w...

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Abstract

3-(3-chloro-1H-pyrazol-1-yl)pyridine is prepared by cyclizing 3-hydrazinopyridine-*dihydrochloride with a dialkyl maleate to provide an alkyl 5-oxo-2-(pyridin-3-yl)pyrazolidine-3-carboxylate, by chlorinating to provide an alkyl 3-chloro-1-(pyridin-3-yl)-4,5-dihydro-1H-pyrazole-5-carboxylate, by oxidizing to provide an alkyl 3-chloro-1-(pyridin-3-yl)-1H-pyrazole-5-carboxylate, by converting the ester to the carboxylic acid by hydrolysis to provide 3-chloro-1-(pyridin-3-yl)-1H-pyrazole-5-carboxylic acid hydrochloride, and by removing the carboxylic acid by a decarboxylation reaction.

Description

[0001] Cross References to Related Applications [0002] This application claims the benefit of US Provisional Application Serial No. 62 / 039,128, filed August 19, 2014, the entire contents of which are hereby expressly incorporated by reference into this application. Background technique [0003] The present invention relates to an improved process for the preparation of 3-(3-chloro-1H-pyrazol-1-yl)pyridines. [0004] US 20130288893 (A1 ) describes, inter alia, certain (3-halo-1-(pyridin-3-yl)-1H-pyrazol-4-yl)amides and carbamates and their use as pesticides. The route to this compound involves the preparation of 3-(3-chloro-1H-pyrazol-1-yl)pyridine by direct coupling of 3-bromopyridine with 3-chloropyrazole. 3-Chloropyrazole was prepared by: a) treatment of 1H-pyrazole with 2-dimethylsulfamoyl chloride and sodium hydride to give N,N-dimethyl-1H-pyrazole-1-sulfonamide, b ) treatment of N,N-dimethyl-1H-pyrazole-1-sulfonamide with perchloroethane and n-butyllithium gave 3-chlo...

Claims

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Application Information

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IPC IPC(8): C07D231/14A01N43/46A61K31/415
CPCC07D401/04
Inventor Q·杨B·洛尔斯巴赫D·E·波德霍雷兹
Owner DOW AGROSCIENCES LLC
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